The elimination of casting cores with a rather complex structure very often requires the use of a pneumatic hammer allowing to subject the part to repeated shocks which may break the adherence of sand on the walls.
Initially, this operation was done manually holding the pneumatic hammer and relying on the dexterity and know-how of the operator, which resulted in some disparities in the result achieved and in the rejection of a rather large percentage of finished pieces not completely decored.
In order to rationalize this operation and to protect the operator from resulting nuisances such as noise and dust, the use of devices such as those described in French patent No. 2.311.617 and European patent No. 0.144.031 was considered. Those devices basically consist of a frame onto which one or more decoring parts are mounted while said frame is subject to vibrations likely to cause the unsticking and splitting of the cores.
In order to increase even further the performance of this device, the French patent No. 2.470.652 provides for several frames on a polygonal roundabout driven in step rotation before a loading station and an unloading station diametrically opposite.
However, it should be noted that the vibrations thus regularly applied to the pieces do not ensure adequate splitting of the core, or full unsticking of all fragments of said core.
The result of this situation is a certain reluctance from the designers to use complex designs which may hinder such decoring although this would be highly desirable for the future use of the piece.
This problem is of special significance for internal combustion motor cylinder heads where the most complex designs are very often impossible to fully decore, with the trouble this implies in assembly lines and the fact that designers give up on such designs.
The purpose of this invention is to correct all those disadvantages. This invention, as described, solves the problem of defining a process and creating devices with which the cores cannot only be split up but also fully disintegrated while causing an erosion effect which leads to the unsticking of all sand particles before full gravity discharge in one single phase, preferably without repositioning the piece on its support.